A Josephson traveling wave parametric amplifier featuring superconducting nonlinear asymmetric inductive elements.

We present our latest experimental results on Josephson traveling wave parametric amplifiers (TWPAs) fabricated with our Nb/Al-AlOx/Nb junction process [1,2] tailored for the readout of superconducting quantum bits. Our TWPA exhibits gain in excess of 15 dB across 4-9 GHz in three-wave mixing. The device design features superconducting nonlinear asymmetric inductive elements (SNAILs), an integrated on-chip magnetic flux bias line, as well as engineered dispersion for the control of the second harmonic generation of the pump tone. We compare the experimental results to predictions from coupled mode equations.

[1] Leif Grönberg et al., Superconductor Science and Technology 30, 125016 (2017)
[2] Slawomir Simbierowicz et al., arXiv:2009.03010